Pulp composition for paper and solid board production

Abstract

The present invention relates to a novel pulp composition for paper or solid board production comprising an oxidized recovered paper pulp and / or an oxidized mechanical pulp into which from 1 to 500 mmol of carboxyl groups per kg and from 1 to 200 mmol of aldehyde groups per kg have been introduced by oxidation. The invention also relates to paper and solid board based on such a pulp composition and also to a process for producing such paper or solid board. The invention also relates to the use of oxidized recovered paper pulp and / or oxidized mechanical pulp for improving the retention and drainage properties of a pulp suitable for producing paper or solid board. The invention further relates to the use of oxidized recovered paper pulp and / or oxidized mechanical pulp for improving, i.e., increasing, the dry strength of paper and solid board.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority under 119(e) of U.S. Provisional Application No. 61 / 331,420, filed May 5, 2010.[0002]The present invention relates to a novel pulp composition for paper or solid board production, said novel pulp composition comprising an oxidized recovered paper pulp and / or an oxidized mechanical pulp. The invention also relates to paper and solid board based on such a pulp composition and also to a process for producing such paper or solid board. The invention also relates to the use of oxidized recovered paper pulp and / or oxidized mechanical pulp for improving the retention and drainage properties of a stock suitable for the production of paper or solid board. The invention further relates to the use of oxidized recovered paper pulp and / or oxidized mechanical pulp for improving, i.e., increasing, the dry strength of paper and solid board.BACKGROUND OF THE INVENTION[0003]Many papers are currently produced ...

AI Technical Summary

Benefits of technology

The present invention provides a pulp composition that improves the retention properties and drainage properties of paper or solid board production. By using an oxidized pulp that has been introduced with carboxyl and aldehyde groups, the pulp composition increases the first pass retention and ash retention, as well as improves the dry strength properties of paper or solid board. This allows for a higher proportion of recovered paper and mechanical pulp in the pulp composition, without compromising the dry strength properties. The use of oxidized pulp also reduces the amount of chemical pulp needed. Additionally, the oxidized pulp improves the drainage properties of aqueous fiber suspensions, making it easier to produce paper or solid board with the desired properties.

Problems solved by technology

However, the quality of the recovered paper pulp frequently leaves something to be desired when in the course of recycling paper and solid board or in the course of the mechanical destructurization of wood the structure of the fibers is damaged, which leads to lower strength values in the paper.

Accordingly, the amount of recovered paper pulp or of mechanical pulp in the paper stock used for producing paper and solid board is limited.

Although the use of oxidized pulps is described in the prior art cited here, such oxidized pulps have hitherto not been used in the paper industry.

One reason for this may be that the oxidation damages the cellulose fibers structurally, which leads to a worsening in the dry strength properties of the paper, more particularly the (tongue) tear energy.

However, this is not desirable in many cases, since this distinctly increases the energy requirements for reprocessing the paper.

A further problem in the production of paper or solid board is the often unsatisfactory retention property of the pulp compositions used for paper or solid board production, more particularly of those kinds of pulp compositions which include a high proportion of recovered paper and / or mechanical or thermomechanical pulp, requiring larger amounts of retention aids to be used.

Often, the drainage properties of the pulp compositions are also unsatisfactory.